At least three lanes were blocked. The backup stretched for several miles.

Troopers said a witness reported that the Mazda was being driven erratically shortly before the crash. A Bellingham woman, 58, was behind the steering wheel and is being investigated for drunken driving, Francis said.

The Mazda drove onto the right shoulder and hit a concrete barrier. The car then spun across all four lanes before crashing into an SUV, Francis said.

The SUV rolled onto a jersey barrier before ending up on its side in the carpool lane.

The SUV driver — a Florida man, 51 — was not injured.

His passenger — a Florida woman, 43 — was taken to Providence Regional Medical Center Everett with possible rib injuries.